Explain why evolution by natural selection can not occur if there is no variation in a characteristic

How does the way animal cells use their vacuoles compare to the way plant cells use theirs?

Convention is when warm air rises and takes heat with it; eventually it cools and sinks Radiation is when sunlight travels through space without the aid of fluids or solids A. true B. false

Jose wants to investigate how physical activity affects heart rate. What is the testable question?

Which of the following describes how homologous structures provide evidence to support hat life changes over time A. some animals exhibit similar stages of embryonic development B.

Glands that secrete their product by the bursting of cells are

What scientific discovery spurred the rapid advancements in the fields of genetics?

How is a yeast cell different from a onion skin cell

Are genetic defects associated with abnormalities of autosomes or of a sex chromosome

In what way are blood and sap the same

1.) How do photosynthesis and cellular respiration relate to each other? 2.) What is the overall purpose of cellular respiration? Why is cellular respiration important? 3.) What is the overall purpose of photosynthesis? Why is it important?